A seamless pattern made from the gold Penrose triangle by GDJ and the two remixes
Source Firkin
A dark one with geometric shapes and dotted lines.
Source Mohawk Studios
Seamless pattern the tile for which can be had by using shift-alt-I on the selected rectangle in Inkscape.
Source Firkin
I know there is one here already, but this is sexy!
Source Gjermund Gustavsen
A bit strange this one, but nice at the same time.
Source Diogo Silva
Derived from a drawing in 'The Murmur of the Shells', Samuel Cowen, 1879.
Source Firkin
Formed from a tile based on a drawing from 'Viaggi d'un artista nell'America Meridionale', Guido Boggiani, 1895.
Source Firkin
Remixed from a drawing in 'Line and form', Walter Crane, 1914.
Source Firkin
A seamless pattern formed from a tile that can be had in Inkscape by selecting the rectangle and using shift+alt+i.
Source Firkin
This seamless web background texture looks like gray stone. It's great for using as a background image on web pages, or on some of their elements. Anyway, I hope you will find use for it.
Source V. Hartikainen
Sweet and subtle white plaster with hints of noise and grunge.
Source Phil Maurer
A beautiful dark wood pattern, superbly tiled.
Source Omar Alvarado
This one is amazing, truly original. Go use it!
Source Viahorizon
A green background pattern with warped vertical stripes and a grunge look.
Source V. Hartikainen
From an image on opengameart.org shared by rubberduck.
Source Firkin
Inspired by a drawing in 'Kulturgeschichte', Freidrich Hellwald, 1896.
Source Firkin
More carbon fiber for your collections. This time in white or semi-dark gray.
Source Badhon Ebrahim
Just to prove my point, here is a slightly modified dark version.
Source Atle Mo
Some dark 45 degree angles creating a nice pattern. Huge.
Source Dark Sharp Edges
Love the style on this one, very fresh. Diagonal diamond pattern. Get it?
Source INS